Method of treating yarn

ABSTRACT

THE INVENTION RELATES TO A METHOD OF TREATING A TENSIONED YARN WHICH ADVANCES IN A PREDETERMINED DIRECTION. THE METHOD COMPRISES THE STEPS OF ENGAGING SUCCESSIVE PORTIONS OF THE YARN, AND SIMULTANEOUSLY TWISTING AND ADVANCING THE RESPECTIVE ENGAGED YARN PORTIONS AT A RATE REQUISITE FOR OBTAINING A TENSION IN THE YARN WHICH DOWNSTREAM OF THE RESPECTIVE THUS ENGAGED YARN PORTION IS IN THE RANGE OF 0.10 TO 0.17 GRAM PER DENIER, AND WHICH UPSTREAM OF THE THUS ENGAGED YARN PORTION IS IN THE RANGE OF 0.07 TO 0.14 GRAM PER DENIER.

7 w. PARKER 3,555,807

METHOD OF TREATING YARN Filed June 8, 1967 F/GJ m was.

ATTORNEY United States Patent 3,555,807 METHOD OF TREATING YARN Walter Parker, Wilmslow, England, assignor t0 Ernest Scragg & Sons Limited, Macclesfield, Cheshire, England Filed June 8, 1967, Ser. No. 644,657

Int. Cl. D02g 1/02 US. Cl. 57157 14 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to the treatment of yarn in general, and more particularly to a method of treating a tensioned yarn advancing in a predetermined direction. Still more particularly, the present invention relates to a method of simultaneously advancing and crimping a yarn.

In the art of treating yarn it is known to simultaneously advance yarn in a predetermined direction, and twist the yarn while it moves in such predetermined direction, to thereby effect crimping of the yarn. The difficulty which has heretofore existed in connection with such treatment of the yarn resides in the fact that, as the yarn is twisted, the tension of the yarn is changed both upstream and downstream of the false-twisting device used for the twisting purpose. For a variety of reasons this is highly un desirable and there has long existed in this field an unfilled need for a yarn-treating method of this type in which the yarn tension upstream of the false-twisting arrangement could be maintained at a specific desired value while the yarn tension downstream of the twisting device could be maintained at a second desired value different from the first desired value and uninfluenced thereby.

SUMMARY OF THE INVENTION The present invention provides a method which affords the desired characteristics and advantages.

More particularly, the present invention provides a method of treating a tensioned yarn advancing in a predetermined direction, in which method the. tension of such yarn upstream of the point at which twisting occurs is different from the tension of the yarn downstream of this point, with both tensions being prevented from influencing one another and with both tensionsbeing subject to precise control.

In accordance with one feature of my invention I provide a method of treating a tensioned yarn which advances in a predetermined direction, which method comprises engaging successive portions of this yarn, and simultaneously twisting and advancing the respective engaged yarn portions. The twisting and advancing of such portions is accomplished at a rate requisite for obtaining Patented Jan. 19, 1971 a tension in the yarn which downstream of the respective thus engaged yarn portion is in the range of 0.10 to 0.17 gram per denier, whereas upstream of the thus engaged yarn portion the tension is in the range of 0.07 to 0.14 gram per denier.

In accordance with my invention, which has particular applicability to thermoplastic textile yarn the method set forth above provides for the yarn treated with it certain characteristics which will be discussed below. Thus, it effects the crimp rigidity of the yarn, as well as the tension of the yarn and the tenacity thereof. Inasmuch as an understanding of these terms will be essential for an understanding of the invention, it should be noted that crimp rigidity is a measure of the ability of a crimped yarn to contract after it has been extended. The standard test for crimp rigidity is to fasten a heavy weight on a length of crimped yarn, usually in water at 20 C., and thereupon to remove most of the weight from the length of yarn and to note the percentage contraction of the length. The higher the percentage contraction which takes place, the higher the crimp rigidity.

The expression yarn tension is generally expressed in grams but this is merely a shorthand expression for what actually should be grams/weight. Thus, a tension of, say, 5 grams/weight is that tension which is produced by securing on and hanging from a length of yarn a. weight of 5 grams.

Finally, the term tenacity as applied to a yarn is the load or tensionagain expressed in grams or, more properly grams/Weightat which the yarn breaks.

With the above explanations in mind it can be said that, in accordance with another feature of my invention, the yarn tension upstream and downstream of the point at which the yarn is subjected to twisting, is Such that for a -denier 34-filament nylon yarn, the yarn has a crimp rigidly of above 40%, and preferably above 50%, as determined by the Hatra test at 20 C. For yarns of other composition the crimp" rigidity has a correspondingly elevated value. Thus, in a 70-denier 34-filament nylon yarn, the tension in the yarn upstream of the point at which the yarn is being twisted will in accordance with the invention be approximately 5 to 9 grams, whereas the tension in the yarn downstream of the point at which the yarn is being twisted will be between approximately 8 and 12 grams.

Yarn treated in accordance with the method disclosed herein may have a tenacity of between 4 and 5 grams per denier downstream of the point at which it is being twisted.

My invention also contemplates heating the yarn while the latter is in a twisted condition and upstream of the point at which the twisting of the yarn occurs. The temperature to which the yarn is heated ranges, if the yarn is a nylon yarn, preferably between 238 C. and 250 C but definitely below the latter value.

In accordance with the invention the yarn, which can advantageously be forwarded or advanced at a linear speed of yards per minute or more, can also be subjected to a post-treatment downstream of the point at which it is subjected to twisting. Such post-treatment is for the purpose of reducing the crimp elongation of the yarn to thereby obtain a yarn whose crimp elongation preferably ranges between 5% and 35%. This posttreatment may, also in accordance with the invention, comprise heating of the yarn downstream of the point at which the yarn is twisted and while the yarn advances with the twist partially relaxed or removed. However, I also contemplate as an alternative to wind the crimped yarn in partially relaxed state into the form of a yarn package and to subsequently subject such package to the influence of a fluid at elevated temperature to thereby effect the desired reduction in the crimp elongation of the yarn. It is to be understood that the term partially relaxed as used with reference to twist crimped yarns describes the state of the crimped yarn after the yarn has been extended so as to remove some but not all of the crimp from the yarn.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustration of an arrangement for practicing the method disclosed herein;

FIG. 2 is a somewhat diagrammatic elevational view of an apparatus suitable for carrying out the novel method;

FIG. 3 is a view of the apparatus as seen in the direction of the arrows 22 of FIG. 1; and

FIG. 4 is a fragmentary perspective view of drive means for use in the apparatus shown in FIGS. 2 and 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail, and firstly FIG. 1 thereof, it will be seen that the arrangement illustrated therein comprises a yarn package or bobbin 113 from which a yarn 110 is withdrawn over a yarn stabilizer 112 via a conventional yarn feeding and twist-stopping arrangement 111. Thereupon the yarn 110 passes through a conventional yarn heater 114 which is so well known in the art that a specific description is not believed to be necessary. After being heated in the yarn heater to the temperature described earlier or to a temperature within the range set forth above, the yarn passes to an apparatus 115 which is illustrated in detail in FIGS. 2-4 and which serves to simultaneously advance and twist the yarn. Downstream of the apparatus 115, the yarn 110 is engaged by a yarn forwarding roller arrangement 116 which advances the yarn to suitable windup means of any well known type, here illustrated as a rotating yarn package 117, a package-rotating ball or member 118 and an oscillating traverse guide 119, all of which are conventional.

The apparatus 115 for carrying out my novel method is illustrated in detail in FIGS. 24. Referring firstly to FIG. 2, it will be seen that the apparatus comprises a first plurality of disclike members 13 and a second plurality of disclike members 14, all of which are of circular outline. The members 13, 14 are arranged in sets of which only three are shown in FIG. 2 although another number can be provided, with ten being the preferred number of sets. Each set consists of two of the members 13 which are axially spaced from one another and are arranged on a shaft 16 which is adapted for rotation about its longitudinal axis, to thereby rotate the members 13 about their respective longitudinal axes. Additionally each set comprises one of the members 14 which is arranged intermediate the members 13 of the same set, spaced axially from either one of these members 13, and which is arranged for rotation about an axis parallel to, but laterally offset from the axis of rotation defined by the shaft 16. For the sake of simplicity it is assumed that each set comprises two of these shafts 16, with one hav- 4 ing the members 13 mounted thereon and the other having the member 14 mounted thereon. This arrangement is clearly illustrated in FIG. 3 and is even more definitely shown in FIG. 4.

In addition to being rotatable about their respective longitudinal axes, the shafts 16 are'also mounted for rotation in a circular path, as illustrated in FIG. 2, about an axis of rotation defined by a shaft 22. FIG. 1 shows clearly that the axis of each of the shafts 16 extends tangentially to the circular path in which each set consisting of the two members 13, the single member 14, and the two shafts 16, revolves about the axis defined by shaft 22.

Belt-drive means 12 is provided, as shown in FIGS. 24, and is arranged for rotating at least one of the shafts 16 of each set about the longitudinal axis of the respective shaft. The belt-drive means 12 is operatively connected with the shaft 22 to be advanced in response to rotation of the latter. As shown in the figures, the members 13, 14 all have equal radii and the shaft members 16 each are engaged by the belt means 12 are provided with belt-engaging portions 17, which are also all of equal radius.

FIGS. 3 and 4 show most clearly that a belt 18 of the belt drive means 12 drives adjacent ones of the shaft members 16 and engages, intermediate such shaft members, idler means which comprises an idler pulley 19 adapted to revolve with the sets of members 13, 14 and rotate about a shaft 21. It is advantageous to so mount the idler pulley 19 that its distance from the shaft members 16 can be adjusted to permit changes in the length of the belts which result inevitably from aging of the belt material. One manner in which this mounting may be accomplished is to provide a bearing mounted on the shaft so as to be adapted for rotation about an axis which does not pass through the center of the bearing, such bearing being capable of being fixed in any desired angular position. This is not illustrated, however, because it does not constiute a part of the invention and has been mentioned here only by way of example.

As is clearly evident from the drawing, the belt 18 engages a first pulley 23 which is fixedly secured on the shaft 22, and it further engages a second pulley 24 which is provided on rotatable with reference to the shaft 22, it being evident from FIG. 3 that the pulley 24 is axially spaced from the pulley 23 along the shaft 22. Intermediate the pulleys 23 and 24, the belt 18 also engages idler means which includes an idler pulley 25 mounted for rotation on the shaft 21 and therefore adapted to revolve in the aforementioned circular path, illustrated in FIG. 1 in chain-link lines, with the sets of members 13, 14.

The embodiment of FIG. 3 differs slightly from what has just been said in that it assumes that both of the pulleys 23 and 24 are capable of rotation with reference to the shaft 22. To this end the embodiment of FIG. 3 comprises a tongued member 26 which is slidable in an axially extending groove provided in the shaft 22 between a first position in which a tongue of the member 26 engages one of the pulleys 23, 24 to fix it against rotation with reference to the shaft 22, and a second position in which another tongue engages the other of these pulleys 23, 24 to fix this other pulley in a similar manner. Thus, the member 26 permits selective fixing or securing of either of the pulleys 23, 24 against rotation with reference to the shaft 22 whenever this is desired. An operating portion 27 extending clear of the belt-drive means 12 is connected with the member 26 so as to enable an operator to effect fixing of the pulleys 23, 24 in dependence upon the momentary requirements. It will be evident that which ever one of the pulleys 23, 24 is secured is determinative of the direction of rotation of sets of members 13, 14 in relationship to a given direction of rotation of the shaft 22.

The yarn 10, coming from the heater (not illustrated in FIGS. 24 but corresponding to the heater 114 in FIG. 1), passes onto the first set of members 13, 14 in such a manner that it is in engagement with the surfaces 20 of the members 13, 14, as shown in FIG. 4. The shafts 16, and in the illustrated embodiment, particularly that shaft 13 of each set which carries the members 13 are interconnected by suitable flexible rotary drive-transmitting means 15, and the shafts 16 of each set which carry the members 14 are similarly interconnected. Thus, as the yarn passes onto the surfaces 20 of one of the sets of members 13, 14, it is simultaneously twisted by rotation of members 13, 14 of the respective set in the direction of the arrows shown in FIG. 4, and also advanced by engagement with these members in the direction of the rotary path in which each set of members 13, 14 travels, in the sense shown in FIG. 1 by the arrow associated with the shaft 22. The path in which the yarn 10 is disposed from the time at which it is first engaged by one of the sets of members 13, 14 to the time at which it is released, defines a substantially crunodal loop and it is in this path that the yarn 10 is twisted by rotation of the members 13, 14 transversely of the path which these same members describe in revolving about the shaft 22. At the same time the yarn 10 is advanced in longitudinal direction by such movement of the sets of members 13, 14 in the circular path about the shaft 22. The twist which is imparted to the yarn 10 extends upstream from the position at which the yarn leaves the apparatus shown.

It is clear that, because the apparatus is effected not only for false twisting the yarn, but also for advancing it in the sense shown in FIG. 2, yarn tension downstream of the apparatus is substantially without any influence on the tension of the yarn upstream thereof so that the apparatus effectively isolates what might be called the yarn input from what might be called the yarn output.

In accordance with the invention the heater, which is known per se and illustrated in FIG. 1 at reference numeral 114, may be of the direct-contact type having a yarn contact surface of approximately 12 feet in length. It is advantageous that this surface be maintained at a temperature of 244 C. nominal and that if for instance a. 34-filament nylon yarn of 70 denier is to be treated in accordance with the present method, such yarn be forwarded at a rate requisite for maintaining each portion of the advancing yarn in contact with the heater contact surface for a period of 2 seconds. It is advantageous that the tension in the twist yarn as it contacts the heater surface be held in the range between 6.5 and 7.5 grams, and the tension in the false twist crimped yarn which issues from the apparatus of FIGS. 2-4 will be substantially 10 grams. In accordance with the invention it is also advantageous that the transverse speed of the roller arrangements consisting of members 13, 1-4 namely the speed of rotation of these members about their respective axes be equal to twice the speed at which each of the sets consisting of the rollers 13, 14 advances in its circular path about the axis defined by the shaft 22.

The yarn which is produced in accordance with the method of the present invention is fully torque crimped but may be post-treated if it is desired to produce a modified torque crimped yarn having a reduced crimpelongation in the range of between 5 and 35 percent. To achieve this modification, the post-treatment may be either a continuous process, in which the yarn is heated again downstream of the apparatus shown in FIGS. 2-4, and while still advancing in a partially relaxed state, or the yarn may be Wound in such partially relaxed state into a yarn package which is then subsequently subjected to the influence of a heated fluid, for instance steam, to obtain the reduced crimp elongation in the range between 5 and 35 percent.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of applications differing from the types described above.

While the invention has been illustrated and described as embodied in a method of treating yarn, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended withinthe meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A method of treating a tensioned yarn advancing in a predetermined direction, comprising engaging successive portions of said yarn; and simultaneously twisting and advancing the respective engaged yarn portions at a rate requisite for obtaining a tension in the yarn which downstream of the respective thus engaged yarn portion is in k the range of 0.10 to 0.17 gram per denier, and which upstream of the thus engaged yarn portion is in the range of 0.07 to 0.14 gram per denier.

2. A method as defined in claim 1, wherein the step of simultaneously twisting and advancing comprises exerting on said engaged yarn portion a force having a first component of movement effecting advancement of said yarn in said predetermined direction, and a second component of movement transverse to said first component of movement and eflfecting twisting of the yarn.

3. A method as defined in claim 2, wherein the rate of movement of said second component is substantially double the rate of movement of said first component.

4. A method as defined in claim 1, wherein said yarn is a 70-denier thirty-four filament nylon yarn, and wherein the tension obtained in said yarn is such as to impart to said yarn a crimp rigidity in excess of 40%.

5. A method as defined in claim 4, wherein the tension in said yarn downstream of said engaged portion ranges between 8 and 12 grams, and the tension in said yarn upstream of said engaged portions ranges between 1 and 9 grams.

6. A method as defined in claim 1, wherein the tenacity of said yarn downstream of said engaged portion ranges substantially between 4 and 5 grams per denier.

7. A method as defined in claim 1; and further comprising the step of heating said engaged yarn portions preliminary to engagement thereof for a period of 'between 0.4 and 2.0 seconds.

8. A method as defined in claim 1, wherein said yarn is a nylon yarn; and further comprising the step of heat-\ ing said engaged yarn portion preliminary to engagement thereof to a temperature of up to 250 centigrade.

9. A method as defined in claim 8, wherein said temperature ranges between 238 C. and 250 C.

10. A method as defined in claim 1, wherein the increments of said yarn which are located downstream of said engaged yarn portion have a predetermined crimp elongation; and further comprising the step of treating said increments to thereby reduce said crimp elongation.

11. A method as defined in claim 10, wherein the step of treating said increments comprises partially relaxing and heating the advancing increments.

12. A method as defined in claim 10, wherein the step of treating said increments comprising partially relaxing said increments, winding said increments into a yarn package, and subjecting said yarn package to the influence of a fluid at elevated temperature.

13. A method as defined in claim 1, wherein the increments of said yarn which are located downstream of said engaged yarn portion have a predetermined crimp elongation; and further comprising the step of treating said increments so as to reduce said crimp elongation to thereby obtain a crimp elongation factor ranging between 5% and 35%.

14. A method as defined in claim 1, wherein the step of engaging said successive yarn portions comprises engaging said yarn portions with an instrumentality which exerts thereon both a twisting action and a forwarding action for simultaneously twisting and advancing the respective yarn portions.

References Cited UNITED STATES PATENTS 3,328,950 7/1967 Scragg et a1 5777.42

FOREIGN PATENTS 1,398,207 3/1965 France 57-77.4

422,218 4/1967 Switzerland 5734HS JOHN PETRAKES, Primary Examiner 

